fix(app): remember review pane width across sessions, default to smallest

packages/app/src/context/layout-helpers.ts

@@ -1,5 +1,13 @@
 import type { Accessor } from "solid-js"
 
+// The review pane is `flex-1`, so it fills whatever the chat panel leaves — a wider chat
+// means a narrower review pane. When the width was never set (`undefined`), fall back to the
+// widest the chat panel is allowed to be, which is the review pane's smallest state, so the
+// review pane starts minimized instead of grabbing the whole remainder of a wide monitor.
+export function resolveSessionWidth(stored: number | undefined, maxWidth: number) {
+  return stored ?? maxWidth
+}
+
 export function ensureSessionKey(key: string, touch: (key: string) => void, seed: (key: string) => void) {
   touch(key)
   seed(key)

packages/app/src/context/layout.test.ts

@@ -1,6 +1,20 @@
 import { describe, expect, test } from "bun:test"
 import { createRoot, createSignal } from "solid-js"
-import { createSessionKeyReader, ensureSessionKey, pruneSessionKeys } from "./layout-helpers"
+import { createSessionKeyReader, ensureSessionKey, pruneSessionKeys, resolveSessionWidth } from "./layout-helpers"
+
+describe("resolveSessionWidth", () => {
+  test("defaults to the max chat width (smallest review pane) when never set", () => {
+    expect(resolveSessionWidth(undefined, 900)).toBe(900)
+  })
+
+  test("uses the remembered width once the user has resized", () => {
+    expect(resolveSessionWidth(720, 900)).toBe(720)
+  })
+
+  test("keeps a remembered width of zero rather than falling back", () => {
+    expect(resolveSessionWidth(0, 900)).toBe(0)
+  })
+})
 
 describe("layout session-key helpers", () => {
   test("couples touch and scroll seed in order", () => {

packages/app/src/context/layout.tsx

@@ -15,7 +15,7 @@ import { createScrollPersistence, type SessionScroll } from "./layout-scroll"
 import { createPathHelpers } from "./file/path"
 import type { ProjectAvatarVariant } from "@opencode-ai/ui/v2/project-avatar-v2"
 import { migrateLegacySessionStateKeys, ServerScope, SessionStateKey } from "@/utils/server-scope"
-import { createSessionKeyReader, ensureSessionKey, pruneSessionKeys } from "./layout-helpers"
+import { createSessionKeyReader, ensureSessionKey, pruneSessionKeys, resolveSessionWidth } from "./layout-helpers"
 import { requireServerKey } from "@/utils/session-route"
 import { type DraftTab, useTabs } from "./tabs"
 
@@ -28,6 +28,11 @@ const DEFAULT_SIDEBAR_WIDTH = 344
 const DEFAULT_FILE_TREE_WIDTH = 200
 const DEFAULT_SESSION_WIDTH = 600
 const DEFAULT_TERMINAL_HEIGHT = 280
+
+// Widest the chat panel is allowed to be (mirrors the `max` clamp on the resize handle),
+// which is the review pane's smallest state. `resolveSessionWidth` uses it as the first-open
+// default. SSR has no window, so fall back to the static default there.
+const maxSessionWidth = () => (typeof window === "undefined" ? DEFAULT_SESSION_WIDTH : window.innerWidth * 0.45)
 export type AvatarColorKey = (typeof AVATAR_COLOR_KEYS)[number]
 
 export function getAvatarColors(key?: string) {
@@ -286,9 +291,6 @@ export const { use: useLayout, provider: LayoutProvider } = createSimpleContext(
           width: DEFAULT_FILE_TREE_WIDTH,
           tab: "changes" as "changes" | "all",
         },
-        session: {
-          width: DEFAULT_SESSION_WIDTH,
-        },
         mobileSidebar: {
           opened: false,
         },
@@ -303,6 +305,15 @@ export const { use: useLayout, provider: LayoutProvider } = createSimpleContext(
       }),
     )
 
+    // Chat/review split width lives in the shared global scope, not the per-server layout
+    // store, so a width the user sets in one session is remembered across every session and
+    // server (each Forge task connects to its own server). `undefined` marks "never resized",
+    // which the getter resolves to the smallest review pane at read time.
+    const [sessionWidthStore, setSessionWidthStore] = persisted(
+      Persist.global("layout-session-width"),
+      createStore({ width: undefined as number | undefined }),
+    )
+
     const MAX_SESSION_KEYS = 50
     const PENDING_MESSAGE_TTL_MS = 2 * 60 * 1000
     const usage = {
@@ -709,13 +720,9 @@ export const { use: useLayout, provider: LayoutProvider } = createSimpleContext(
         },
       },
       session: {
-        width: createMemo(() => store.session?.width ?? DEFAULT_SESSION_WIDTH),
+        width: createMemo(() => resolveSessionWidth(sessionWidthStore.width, maxSessionWidth())),
         resize(width: number) {
-          if (!store.session) {
-            setStore("session", { width })
-            return
-          }
-          setStore("session", "width", width)
+          setSessionWidthStore("width", width)
         },
       },
       mobileSidebar: {